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Abstract:

A leak detecting and leak protecting circuit comprises a rectification
circuit comprising positive and negative power output ends, current
limiting resistors, a diode, a silicon control comprising control poles,
a switch capable of linking to a resetting button, and a tripping coil
comprising a built-in iron core. The rectification circuit outputs DC
power. The tripping coil, switch, and silicon control are connected in
series and then are connected to the positive and negative power output
ends of the DC power output from the rectification circuit. The control
poles of the silicon control are capable of connection with a shielding
layer of output wires through at least one of the current limiting
resistors and a diode. And, when the switch is in a resetting state, the
switch is closed, and, when the switch is in a tripped state, the switch
is open.

Claims:

1. A leak detecting and leak protecting circuit, comprising: a
rectification circuit comprising positive and negative power output ends;
current limiting resistors; a diode; a silicon control comprising control
poles; a switch capable of linking to a resetting button; and a tripping
coil comprising a built-in iron core, wherein the rectification circuit
outputs DC power, wherein the tripping coil, switch, and silicon control
are connected in series and then are connected to the positive and
negative power output ends of the DC power output from the rectification
circuit, wherein the control poles of the silicon control are capable of
connection with a shielding layer of output wires through at least one of
the current limiting resistors and a diode, and wherein, when the switch
is in a resetting state, the switch is closed, and, when the switch is in
a tripped state, the switch is open.

2. The circuit of claim 1, further comprising a resetting button,
wherein, when the resetting button is pressed down it places the switch
in the resetting state, and, when the resetting button is in a tripped
state, the switch is open.

3. The circuit of claim 1, further comprising: a failure indicating light
emitting diode for indicating an electrical leak; a power output
indicator light emitting diode for indicating power output through the
circuit; a live line load connection on a load side of the circuit; and a
zero line load connection on the load side of the circuit, wherein the
failure indicating light emitting diode is connected in parallel to ends
of the switch, wherein, when an electrical leak is detected by the
circuit the failure indicating light emitting diode is emitting light,
wherein, when an electrical leak is detected by the circuit and the
switch is in a resetting state, the switch is open, and the failure
indicating light emitting diode is emitting light, and wherein the power
output indicating light emitting diode is connected in parallel to the
live line load connection and the zero line load connection.

4. The circuit of claim 3, further comprising a timing chip comprising a
control signal output end, wherein the control signal output end is
connected with a control pole of the silicon control, wherein the timing
chip outputs a control signal at a predetermined interval to break over
the silicon control, and wherein the control signal is of sufficient
power to test whether the circuit provides leak detection and leak
protection functions.

5. The circuit of claim 1, further comprising a timing chip comprising a
control signal output end, wherein the control signal output end is
connected with a control pole of the silicon control, wherein the timing
chip outputs a control signal at a predetermined interval to break over
the silicon control, and wherein the control signal is of sufficient
power to test whether the circuit provides leak detection and leak
protection functions.

6. The circuit of claim 4, further comprising: a test switch capable of
coupling to a manual test button; and a live line power input connection
on a line side of the circuit, wherein a control pole of the silicon
control is connected to the live line power input connection through a
current-limiting resistor and the test switch to form a simulated leak
circuit.

7. The circuit of claim 6, further comprising a manual test button
coupled to the test switch, wherein, when the test button is pressed
down, the test switch is in a closed state.

8. The circuit of claim 6, further comprising: a zero line power input
connection on a line side of the circuit, wherein the rectification
circuit is a bridge rectification circuit comprising four rectification
diodes and an AC power input end, and wherein the AC power input end is
connected across the live line power input connection and the zero line
power input connection.

9. The circuit of claim 8, wherein the bridge rectification circuit
comprises an AC power output end, and wherein the AC power output end is
connected across the live line load connection and the zero line load
connection.

10. The circuit of claim 9, further comprising: a first triangular
discharging metal sheet on the live line power input connection; and a
second triangular discharging metal sheet on the zero line power input
connection, wherein the first triangular discharging metal sheet and the
second triangular discharging metal sheet are capable of discharging
electricity, wherein first triangular discharging metal sheet and the
second triangular discharging metal sheet are spaced apart with tips of
the respective triangles facing one another, and wherein the first
triangular discharging metal sheet is one of a right triangle or an
isosceles triangle and the second triangular discharging metal sheet is
one of a right triangle or an isosceles triangle.

11. The circuit of claim 8, further comprising: a first triangular
discharging metal sheet on the live line power input connection; and a
second triangular discharging metal sheet on the zero line power input
connection, wherein the first triangular discharging metal sheet and the
second triangular discharging metal sheet are capable of discharging
electricity, wherein the first triangular discharging metal sheet and the
second triangular discharging metal sheet are spaced apart with tips of
the respective triangles facing one another, and wherein the first
triangular discharging metal sheet is one of a right triangle or an
isosceles triangle and the second triangular discharging metal sheet is
one of a right triangle or an isosceles triangle.

12. The circuit of claim 10, further comprising a MOV piezoresistor,
wherein the silicon control comprises an anode and a cathode, and wherein
the MOV piezoresistor is connected in parallel between the anode and the
cathode of the silicon control.

Description:

TECHNICAL FIELD

[0001] The present disclosure relates generally to leak detection and leak
protection electrical circuits for power sockets and power plugs.

BACKGROUND

[0002] Along with the continuous development of the industry of power
sockets and plugs that have leakage protective functions, higher and
higher requirements are proposed for the safe utilization of power
sockets and power supplies with leakage protective functions. People hope
that it should be possible to examine regularly if the leakage protective
plug/socket has a leakage protective function while the plug/socket is in
service. In this way, when its life terminates, i.e. the internal
elements are rendered ineffective and the leakage protective function is
lost, the user can be reminded in time to replace it with a new product.

SUMMARY

[0003] Concerning the above reasons, Applicant proposes a leakage
detection protective circuit which has a compact circuit and stable and
reliable performance. The circuit can be examined regularly to determine
if a power plug or socket has a leakage protective function and the
circuit can display the examination result.

[0004] The circuit also provides protection in the event of a lightning
strike and provides protection from electrophoresis.

[0005] In one embodiment, a leak detecting and leak protecting circuit
comprises a rectification circuit comprising positive and negative power
output ends, current limiting resistors, a diode, a silicon control
comprising control poles, a switch capable of linking to a resetting
button, and a tripping coil comprising a built-in iron core. The
rectification circuit outputs DC power. The tripping coil, switch, and
silicon control are connected in series and then are connected to the
positive and negative power output ends of the DC power output from the
rectification circuit. The control poles of the silicon control are
capable of connection with a shielding layer of output wires through at
least one of the current limiting resistors and a diode. And, when the
switch is in a resetting state, the switch is closed, and, when the
switch is in a tripped state, the switch is open.

[0006] It is to be understood that both the foregoing general description
and the following detailed description are exemplary and explanatory only
and are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The accompanying drawings, which are incorporated in and constitute
a part of this specification, illustrate several embodiments of the
invention and together with the description, serve to explain the
principles of the invention.

[0008] FIG. 1A is a first example of a circuit diagram for a leakage
detection protective circuit.

[0009] FIG. 1B is a second example of a circuit diagram for a leakage
detection protective circuit.

[0010]FIG. 2A is a third example of a circuit diagram for a leakage
detection protective circuit.

[0011] FIG. 2B is a fourth example of a circuit diagram for a leakage
detection protective circuit.

DETAILED DESCRIPTION

[0012] Reference will now be made in detail to the present exemplary
embodiments, examples of which are illustrated in the accompanying
drawings. Wherever possible, the same reference numbers will be used
throughout the drawings to refer to the same or like parts.

[0013] A leakage detection protective circuit has a compact circuit and
stable and reliable performance. The circuit can be examined regularly to
determine if a power plug or socket has a leakage protective function and
the circuit can display the examination result.

[0014] The leakage detection protective circuit may also include a failure
indicator for indicating the leakage failure and a power output indicator
for indicating whether the leakage detection protective circuit has power
output. In the case that leakage failure exists in the power supply
circuit of the power plug/socket, the failure indicator is on. In the
case that leakage failure occurs when the resetting button is in the
resetting state, the resetting button trips, and the failure indicator is
on.

[0015] A timing chip may output a control signal at a certain interval to
trigger a break over of a silicon control to examine regularly whether
the power socket/plug still has a leakage protective function.

[0016] FIG. 1A is a circuit diagram of a possible implementation of
Example 1, where the leakage detection protective circuit is applied in a
power socket/plug to give it a leakage protective function. As shown in
FIG. 1A, this leakage detection protective circuit is composed of a
rectification circuit with rectifier diodes V1-V4, current-limiting
resistors R1-R6, diode V5, silicon control V6, trip switch K3 linked with
resetting button RESET and tripping coil L1 (SOL) with a built-in iron
core. The silicon control V6 may be, for example, a silicon-controlled
rectifier (SCR).

[0017] The action of the iron core built in the tripping coil L1 can make
the resetting button RESET reset or trip. The tripping coil L1 with
built-in iron core, trip switch K3 linked with resetting button RESET and
silicon control V6 are connected in series, and then are connected to the
positive and negative power output ends of the DC power supply output
from the rectification circuit V1-V4.

[0018] The control poles of the silicon control V6 are connected with the
shielding layer of the power socket/plug power output wires through the
current-limiting resistor R3, diode V5 and current-limiting resistor R2
respectively. The power output live line HOT, zero line WHITE and safety
grounding line PE of the power socket/plug are wrapped in the shielding
layer, which is composed of alloy wires (copper, iron, etc.), by
braiding. When leakage exists in the power socket/plug, and because the
current of the working load is often relatively high, the plastic
protective sleeve wrapping on the exterior of the power live line, zero
line or safety grounding line starts to soften and even melts. This
causes the insulation layer to break and to contact with the shielding
layer and subsequently causes the shielding layer to be electrified. When
the shielding layer is electrified, it is possible to judge the existence
of a leakage failure in the power socket/plug quickly and accurately.

[0019] When the resetting button RESET is in a tripped state, the trip
switch K3 linked with the resetting button RESET is open. When the
resetting button RESET is pressed down and when the resetting button
RESET is in a resetting state, the trip switch K3 linked with resetting
button RESET is closed.

[0020] When the resetting button RESET is reset, the transfer switches K1
and K2, and trip switch K3 linked with resetting button RESET are closed.
The working load side LOAD of the power socket/plug has power output. If
a leakage phenomenon (leakage failure) exists in the power supply
circuit, the shielding layer will be electrified, the control pole of the
silicon control V6 will be at a high level, the silicon control V6 will
be broken over, current will flow through the tripping coil L1, and a
magnetic field will be generated in the tripping coil L1. The built-in
iron core will act to make the resetting button RESET trip and to
disconnect the transfer switches K1 and K2 linked with the resetting
button RESET in the main power supply circuit in the power socket/plug,
thereby allowing no power output from the power socket/plug.

[0021] To indicate the state of the power socket, in this utility model, a
failure indicator light emitting diode LED1 for indicating whether
leakage failure exists is connected in parallel to the two ends of the
trip switch K3 linked with the resetting button RESET.

[0022] When the live line HOT and zero line WHITE of the power input side
LINE of the power socket/plug are connected properly with the power live
line and zero line in the wall, and as the resetting button RESET is in a
tripped state, the trip switch K3 linked with the resetting button RESET
is open. In this case, if a leakage phenomenon exists in the power supply
circuit of the power socket/plug, the shielding layer of the power output
wire will be electrified, the control pole of the silicon control V6 will
be at a high level, the silicon control V6 will be triggered and broken
over, and the failure indicator LED1 will be on to show existence of a
leakage failure. If the failure indicator LED1 is not on, it means no
leakage failure exists in the power supply circuit of the power
socket/plug.

[0023] When the resetting button RESET is pressed down and when the
resetting button RESET is in a resetting state, the trip switch K3 is
closed. If a leakage failure exists in the power supply circuit of the
power socket/plug, the silicon control V6 will be triggered and broken
over immediately, thereby disconnecting the transfer switches K1 and K2
and trip switch K3 linked with the resetting button RESET in the main
power supply circuit of the power socket/plug and allowing no power
output from the power socket/plug. Now the failure indicator LED1 turns
on again. Therefore, when the failure indicator LED 1 is on, it means
that a leakage failure exists in the power supply circuit of the power
socket/plug.

[0024] A power output indicator light emitting diode LED2 is connected in
parallel between the live line HOT and zero line WHITE in the load side
LOAD of the leakage detection protective circuit. When the load side has
power output, LED2 is on. When the load side has no power output, LED2 is
off.

[0025] To examine manually whether the power socket/plug has a leakage
detection protective function, i.e. whether the life of the socket is
terminated, as shown in FIG. 1, the control poles of the silicon control
V6 are also connected with the power live line through the
current-limiting resistors R3 & R1, diode V5 and test switch K4 below the
manual test button TEST. Pressing the test button TEST manually makes the
test switch K4 close and generates a simulated leakage current,
subsequently making the control poles of the silicon control V6 be
connected with the power live line through the current-limiting resistors
R3 & R1 and to achieve high level. If the power socket/plug with a
leakage protective function still has the leakage protective function,
i.e. the life is not terminated, the silicon control V6 will be broken
over, current will flow through the tripping coil L1 to generate a
magnetic field, the built-in iron core will act to make the resetting
button RESET trip and to disconnect the transfer switches K1 and K2 in
the main power supply circuit of the power socket/plug. The power
socket/plug will have no power output. On the contrary, if the life of
the power socket/plug is terminated, the resetting button RESET can not
be tripped or reset.

[0026] In order to regularly examine whether the power socket/plug still
has leakage protective function, as shown in FIG. 1A, a timing chip DSQ
(Model 225\226\227) is added in the leakage detection protective circuit.
The control signal output end of this timing chip DSQ can be connected
with the control pole of the silicon control V6. Timing chip DSQ outputs
a control signal at a certain interval (or is set manually) to break over
the silicon control V6. This causes current to flow through the tripping
coil L1 to generate a magnetic field, making the built-in iron core act
to trip the resetting button RESET. The transfer switches K1 & K2 linked
with the resetting button RESET in the main power supply circuit of the
power socket/plug are disconnected, allowing no power output from the
power socket, in order to examine whether the power socket still has a
leakage protective function.

[0027] As shown in FIG. 1A, the rectification circuit is a bridge
rectification circuit composed of rectifier diodes V1-V4. The
rectification circuit AC power input end is connected to the power live
line HOT and zero line WHITE in the input side LINE of the power
socket/plug.

[0028] To improve the service life of the leakage protective socket/plug
and to avoid damage to the power socket/plug resulting from the
instantaneous high voltage caused by lightning or other reasons, as shown
in FIG. 1A, right triangle or isosceles triangle discharging metal sheets
P1 & P2 are used for discharging. Discharging metal sheets P1 and P2 are
connected respectively at the power input end live line HOT and zero line
WHITE. The discharging metal sheets P1 & P2 are placed with the tips
facing to each other and with a certain spacing kept. A piezoresistor MOV
is connected in parallel between the anode and cathode of the silicon
control V6. The piezoresistor MOV may be, for example, a metal oxide
varistor.

[0029] When an instantaneous high voltage caused by lightning or other
reasons is applied to the power socket/plug, the air medium between the
tip of discharging metal sheet P1 and the tip of discharging metal sheet
P2 is broken down, forming an air discharge. Most of the high voltage is
consumed through the discharging metal sheets P1 and P2. The rest of the
high voltage, which is a small part, is consumed through the tripping
coil SOL and piezoresistor MOV, thereby protecting the power socket/plug
from being damaged by the high voltage.

[0030] In the implementation of example 1, a surge-inhibiting type
piezoresistor is used for the said piezoresistor MOV so that it has the
function of preventing electrophoresis.

[0031] FIG. 1B is a circuit diagram of a possible implementation of
Example 2 of the leakage detection protective circuit, and its difference
from the implementation of Example 1 shown in FIG. 1A is as follows. The
AC power input end of the DC power supply is connected to the live line
HOT and zero line WHITE in the load side LOAD of the power socket/plug.
When the power input end of the power socket/plug is connected properly
with the power wires in the wall, the leakage detection protective
circuit shown in Example 1 is electrified automatically and can work,
while the leakage detection protective circuit shown in Example 2 can
only be electrified and work after the switches K1 & K2 in the main power
supply circuit are closed.

[0032]FIG. 2A is a circuit diagram of a possible implementation of
Example 3 of the leakage detection protective circuit. It differs from
the implementation of Example 1 as follows: The timing chip DSQ connected
with the control pole of the silicon control V6 is omitted.

[0033] FIG. 2B is a circuit diagram of a possible implementation Example 4
of the leakage detection protective circuit. It differs from the
implementation of Example 3 as follows: The AC power input end of the DC
power supply is connected to the live line HOT and zero line WHITE in the
load side LOAD of the power socket.

[0034] The leakage protective circuit model has the following prominent
advantages:

[0035] (1) A user can judge whether the power socket/plug has a leakage
failure by testing whether the shielding layer of the power output wire
of the power socket/plug is electrified. The circuit is simple and
compact, and the performance is stable and reliable.

[0036] (2) A user can regularly examine whether the power socket/plug
still has a leakage detection protective function, i.e. whether the life
is terminated.

[0037] (3) The circuit has the function of preventing the power
socket/plug from damage resulting from the instantaneous high voltage
caused by lightning or other reasons.

[0038] (4) The circuit can be manually examined with the results
displayed.

[0039] The contents described above covers specific implementations of
examples and the technical principles adopted. Any equivalent conversion
based on the technical scheme of this utility model is included in the
scope of protection of this utility model. Various preferred embodiments
have been described with reference to the accompanying drawings. It will,
however, be evident that various other modifications and changes may be
made thereto, and additional embodiments may be implemented, without
departing from the broader scope of the invention as set forth in the
claims that follow. The specification and drawings are accordingly to be
regarded in an illustrative rather than restrictive sense.

[0040] Other embodiments of the invention will be apparent to those
skilled in the art from consideration of the specification and practice
of the invention disclosed herein. It is intended that the specification
and examples be considered as exemplary only, with the true scope and
spirit of the invention being indicated by the following claims.